Lubricant receiving fitting



Jan. 30, 1951 T, A- CAMPBELL 2,539,989

LUBRICANT RECEIVING FITTING Filed June 17, 1946 Patented Jan. 30, 1951 2,539,989 4LUBRICANT RECEIVING FITTING Thomas Arthur Campbell, Chicago, Ill., assignor to Stewart-Warner Corporation, Chicago, Ill., a corporation of Virginia Application Junel', 1946, Serial N0. 677,122

My invention relates generally to lubricant receiving fittings for high pressure lubricating systems, and more particularly to ttings designed to limit the pressure at which lubricant may be supplied to a bearing.

In many forms of bearings, such as those of Y centrifugal water pumps, packings or seals may be damaged if the lubricant is supplied to the bearings thereof under greater than a predetermined pressure.

It is therefore the primary object of my invention to provide an improved lubricant receiving fitting for application to such bearings through which lubricant may be supplied from a high pressure source and yet prevent the pressure' within the bearing from exceeding a predetermined maximum value.

A further object of my inventionis to provide an improved lubricant receiving fitting in which the rate of fiow of lubricant through the fitting' is limited.

When bearings having pressure relief fittings applied thereto are lubricated from a power operated compressor, the compressor builds up a pressure of 6000 or 7000 p. s. i., andwhen the coupler is attached to the fitting and the lubricant control valve opened, a sudden surge of lubricant at these high pressures flows into the fitting and bearing'. This initial high pressure is built up so rapidly that the pressure relief valve may not operate rapidly enough to relieve the pressure, and as a result the bearing is very likely to be subjected to excessive pressures.

It is therefore one of the primary objects Yof the invention to provide means in the fitting which-Will prevent the sudden increase or surge of lubricant under high pressure at the inlet of l, the fitting from being transmitted to the bean ing,4 and this is accomplished by providing a),

' fitting, shown to an enlarged scale;

Fig. v2 is a top plan View thereof;

Figs. 3 and 4 are transverse sectional views taken on the lines 3-3 and 4-4, respectively, of Fig. 1; and

1 claim. (or. 184-105) The fitting disclosedin this application is an improvement of the fitting shown in my copending application Serial No. 617,235, filed Septem- `ber 19, 1945, issued as Patent No. 2497,758 on February 14, 1950. It is also an improvement on the fitting shown in the patent to Ernest W.

Fig.5 is a fragmentary -sqctional view of a Davis, No. 2,087,085.

As shown in the drawings, the fitting comprises a body H3 having a hexagonal wrench engaging portion I6 and a threaded shank I8 by which the fitting is secured tc the bearing to be lubricated. The body i0 has axial counterbores 20, 2|, 22, and 23. A head 25, shaped for engagement with the nozzle or coupler of a lubricant compressor, has a cylindrical portion 28 of reduced diameter, an external annular groove 30, and a swaging shoulder 32. The head 25 is preferably made of a harder material than the body l0 so that when the head is pressed into the upper end of the bore 20, the shoulder 32 of the head will swage a portion of the body at the upper end of the bore 20 into the groove 30, thereby securely locking and sealing the head 26 to the body I0.

YThe head 26 has an inlet opening 34 which leads into a bore 35. The lower end of the head 26 is of reduced diameter to form a tubular portion 38 and to provide a shoulder 40 for engagement by the upper end of a helical spring d2. The lower end of the spring 42 rests upon a shoulder 44 between the bores 2| and 22, and its external diameter is but slightly less than that of the bore 2 I. The lower turn of the spring 42 is preferably ground fiat, and a thin flat washer 45 may be inserted, as shown in Fig. 5, whenever it is required that a predetermined pressure be retained in the bearing without excessive leakage through the pressure relief passageway. A pair of outlet ports 4B extendsradially into the bore 22 and thus provides ports through which excess lubri cant supplied to the fitting may be discharged to the atmosphere.

Within the bore 36 there is a restriction pin 48 having a T-shaped head 5B located within the bore 22. There is adequate clearance between the pin 4B and bore 36 to permit ow of lubricant through the fitting at a reasonable rate, the clearance being inthe order of .002 to .015", although this clearance may be varied, by providing a pin of a different size, when lubricants of high viscosity are to be used, or when the fitting is to be used for a bearing requiring a large quantity of grease.

In using the fitting. the coupler of the lubricant compressor ori other source of lubricant under pressure, is connected to the head 26 in 'a manner fully disclosed in the patent to Joseph Bystricky, No. 2,016,809, and lubricant is pumped into the bearing. The rate at which it may be supplied to the bearing cavity to which the tting is connected will depend mainly upon the effective size of a passageway between the pin 48 and the wall-s of thebore 39. Afterthe bearing cavity is iilledior substantially filled with the lubricant, back pressure will build up against the lower endof the spring i2 and compress the latter to permit relatively free escape of surplus lubricant through the bores 2i and-29 va-nd-v outlet ports 46. The operator. knowing that lubricant is flowing from the ports Iiis thus'apprised of the fact that the bearing cavity has been filled -vl with lubricant under the desired maximum pressure, and the supply of lubricant'is therefore discontinued.

When the fitting isflubricated from a com- ,.-pressor which-operates to maintain. a `predetercated-to. the bearing cavity, due in part tothel inertia of the rapidly flowing grease (Water hammer. eiect).r and partly to the factthat the linertiabf the springZ would notpermit relief ,of thepressvre dnringsuch initial surge. The

.presence ofithepin 138 in the boreprovidessa ...suificient restriction between-the inlet and outlet of. the iitting. that the `energy of the. initial r.pressuresurge isdissipated, vso that.time is aflforded for the operation of the pressure relief valve (-.theflowenturns of the springllZ).

The effectivecross sectional area.of.the.space betweenthewall.ofy the boreAZ Iv and .the external .surface .ofthe tubular portion: 33 ofthel headiof .-.the .fitting `is suicieritIy. greater .than` the .cross --sectionaLareaof the space between. the pin yS8 and .theborefithat the spring l2A Willeiectively determinethemaximum pressure Ywhich caribe built up. inthe' bearing cavity. Thus the fitting forma-pa convenientand. simple. safety.. means to prevent supplying lubricant .to the bearing .at an .excess-ive pressure. VIn this way theoperatorfis ...prevented from harmingibearings which vare sub- .'ectfto damage by excessive pressures. In. many formsv ofmachinery, particularly-those used for textile and food, processing, it. is. essential toA limit .the pressuregat whichv .the lubricantis supplied lto-.theibearings in order. to,.prevent the. lubricant :from beingy discharged...from.thebearings. Such excess. lubricant Y .might readily ,spoi1.the textile torLiood. being processed.

The pin 48 is free to move longitudinally to a limited extent and thus may be forced upwardly by the back pressure of the lubricant in the bearing. The pin d8 thus may perform the additional 5 function of a check valve to close the inlet port 34 after the supply of lubricant to the tting has been discontinued and thereby -prevent any material'fquantitylof lubricant from oozing from the port 34.

d0 While I have shown and described perferred embodiments of my invention, it will be apparent that numerous variations and modifications Athereof may be made without departing from the .underlying principles of the invention. I there- 5 foredesire, by the following claim, to include within the scope of the invention all such variations and modifications by which substantially the results of the invention may be obtained through the use of substantially the same or equivalent 20. means.

.ilclaimz ..A..lubr-icant receiving fitting for attachment itoabearing andvorcoupling to a source of vlubricant under pressure,` comprisinga body having .a plurality of counterbcres ofprcgressivelyfde- .creasingdiameter, ahead secured inthe largest .of said..counterbores,v said-head having an inlet port. and vhaving. ax tubular extension projecting e substantial distance into the fittingvbody, the lower end .portion c-r" saidtubular. extension .pro- .vidin `withk one of the counterbores .in the body relatively .narrowannular passageway, a acoil spring having the lower turn thereof substan- 35-tially..lling thepassagevvay,l means in the body providing free communication between thefpassageway and the atmosphere,l and-apin located .gat--leastin part-in the'tubular extension vof the head and .forming therewith a lubricant r-flow /40 restricting l'.passageway, said -.pin being ,.freely movable With respect to the body and =head:to.a -liifiited-extent, and --being .operable -as a. check valve-t0 close the inlet` port in the'head-,of -the ittingfagainstfsubstantial return owfof lubri- 'THOMAS ARTHUR CAMPBELL.

REFERENCES' CITED .'IhefollowingV references lare of f record.- inthe le ofthis "patent: v

'UNIZIFD STATESTPATENTS 

